With the deepening of the application of photoelectric imaging technology, the measurement of image sensors and imaging system parameters becomes important. The non-uniformity of photoelectric response of image sensor pixels is an important index of the image sensor, which directly affects the imaging quality of the photoelectric imaging system. When measuring the non-uniformity of an image sensor, a widely applied method currently uses an integrating sphere to obtain a surface light source with a uniform irradiance, so as to eliminate the influence of non-uniformity of the light source on the measurement result. Take the plane at a certain distance from the exit of the integrating sphere as the surface light source. Taking into account the needs of practical use, this article added a cylinder as a darkroom between the exit surface of the integrating sphere and the surface light source. In order to obtain better uniformity of light source, the inner surface structure of the cylinder adopts a fine thread structure design. The process and conclusion of the simulation research of various parts of the system using optical simulation software ASAP are described in detail. The simulation studied the effects of the opening ratio of the integrating sphere, the length of the cylindrical darkroom, and the structural parameters of the fine thread on the uniformity of the output light source. The system was implemented in the laboratory and the measured results show that the light source produced by the system achieves the expected uniformity.